Rapid opioid detoxification

ABSTRACT

Rapid opioid detoxification procedures are provided which include sedating a patient with a rapid-acting, safely reversible intravenous anesthetic agent having a very short full recovery period. The patient is administered an opioid antagonist while sedated and can be revived to an ambulatory condition within eight hours of initiating therapy. The described methods for detoxification can be used with dually-addicted patients who have abused opiates, such as heroin, as well as benzodiazepines. Even with these dually-addicted patients, the process is completely reversible early on in the procedure if any adverse complications arise.

FIELD OF THE INVENTION

This invention relates to methods of rapidly detoxifying opioid addicts so as to relieve conscious symptoms, and more particularly, to methods of detoxification employing sedation and a narcotic antagonist while permitting the patient to be ambulatory within eight hours of beginning treatment.

BACKGROUND OF THE INVENTION

Heroin addiction is a growing healthcare problem in the United States. The United States Department of Health and Human Services' Substance Abuse Branch issued a report in December of 1994 stating that the number of emergency department visits directly related to heroin use rose from 48,000 in 1992 to 63,000 in 1993, a 31% increase. The rate of heroin-related episodes per 100,000 people rose 81%, from 15 to 28 per 100,000, between 1990 and 1993. Upon breaking down the heroin-using population into ethnic groups and age groups, it has been demonstrated that all subsets have increased rates of use for this time period.

Human opiate detoxification has been in use for some time. More than 31,000 individuals of the Empire Blue Cross and Blue Shield subscriber base in New York were hospitalized at least once for opiate dependency between 1982 and 1992. The majority of these individuals were working adults, and their principal reason for hospitalization was addiction treatment. Drug detoxification accounted for 96% of the admissions, and the length of stay ranged between five and ten days.

It is widely known that heroin addicts fear and loathe heroin detoxification. For the addict, withdrawal can be like having a massive panic attack, an acute case of Huntington's Chorea, a psychological shock syndrome, and a nasty flu, all rolled into one.

Even if we discount the less than warm reception by addicts, the current method of detoxifying an individual from opiates is flawed in several respects. First of all, it is extremely uncomfortable for individual patients. Second, it can take days, and even weeks, for treatment, and this treatment is very expensive when one considers the overall length of stay at a hospital. Third, it is not very effective. Early relapse is the rule rather than the exception.

These results are not surprising. At the end of customary detoxification therapy there remains a considerable amount of opiates on the receptor sites in the brain of the patient. As these opiates diminish, the individual continues to feel uncomfortable and seeks relief by the administration of another dose of opiates. This can be readily appreciated if one attempts to initiate naltrexone oral antagonist therapy immediately after a standard detoxification in an attempt to interfere with the anticipated relapse. The patient promptly experiences considerable discomfort from the displacement of the remaining opiates from the receptor sites.

In the 1980s, outpatient protocols were developed in an attempt to reduce expenses and to entice more addicts to receive treatment. In one particular therapy, a shortened five-day schedule was employed. On the first day, patients received a naloxone hydrochloride ("naloxone") challenge test at 9:00 a.m., using 0.8 mgs of naloxone, and then were started on clonidine hydrochloride ("clonidine") premedication. Clonidine is a potent antihypertensive agent and stimulates adrenergic receptors in the brain, leading to reduced sympathetic nervous system output. Daily averages of medication were, for day two: clonidine 1.1 mgs and naltrexone 8 mgs; day three: clonidine 0.6 mgs and naltrexone 40 mgs; day four: clonidine 0.3 mgs and naltrexone 50 mgs; and day five: clonidine 0.2 mgs and naltrexone 150 mgs.

In 1990, Loimer et al. described an inpatient technique in which 12 hours after the patient's last dose of opiate, they were sedated with 100 mgs of the barbiturate, methohexitone. This was followed by further injections of 400 mgs of methohexitone and 10 mgs of naloxone. After the narcotic effect had worn off, 2 mgs of naloxone was given intravenously about 30-40 minutes later. This did not elicit any further withdrawal response. This study showed that the acute onset of withdrawal symptoms induced by naloxone in opiate addicts is blocked by barbiturates.

Loimer et al. in 1991 described another inpatient, technique for enabling patients to transfer quickly from methadone to naltrexone maintenance. In a study of seven patients, they induced acute methadone detoxification by using a 4 mg bolus of intravenous naloxone ten minutes after intravenous sedation was started with 30 mgs of midazolam, a short-acting benzodiazepine. After the naloxone infusion was completed, the patients received repeated dosages of flumazenil, a benzodiazepine antagonist, until they were awake. Within hours, the patients tolerated full doses of naltrexone.

Loimer pointed out that conscious sedation with midazolam was safer than general anesthesia. The technique also suppressed withdrawal signs and symptoms. Loimer used intranasal naloxone to induct patients onto naltrexone.

Loimer further described in 1993 an inpatient technique using intranasal naloxone. Twenty opiate-dependent patients reported a mean daily heroin dose of 2.0 grams for at least 2 months prior to detoxification. Twelve hours after their last heroin use, all the patients were sedated with 60 mgs of midazolam. Simultaneously, they received 0.3 mgs of clonidine and 5.0 mgs of ondansetron (a selective 5-HT3 receptor antagonist, generally used to prevent nausea and vomiting associated with cancer chemotherapy). Ten minutes later, oral naltrexone, 50 mgs, was administered. The patients typically were asleep fifteen minutes post-midazolam injection, at which time withdrawal was precipitated by 4 mgs of naloxone administered nasally as a spray. Naltrexone, 50 mgs/day, was continued for the next 2 days before discharge.

Loimer has reported that none of his patients showed severe withdrawal distress before 30 detoxification. He has found that following the administration of naloxone, withdrawal distress was significantly higher than baseline levels at 30, 45, 60 and 90 minutes, but that there were no significant differences from the baseline on all subsequent measurements. Furthermore, he has reported that systolic and diastolic blood pressure and heart rate did not change significantly during treatment.

Legarda and Gossop in 1994 also described an inpatient technique enabling heroin addicts to undergo a rapid transition to naltrexone maintenance, now referred to as rapid opiate detoxification ("ROD"). Legarda belongs to the CITA group, which has been detoxifying heroin patients in Spain, Israel and Mexico under general anesthesia.

As in Loimer et al.'s 1991 report, Legarda and Gossop used intravenous midazolam (0.5-0.7 mgs/kg initially, then as a constant infusion) for sedation. In this study, however, patients received an initial dose of oral naltrexone, 50 mgs, immediately prior to the injection of midazolam, and did not receive any naloxone reversal while under sedation.

They also pretreated the patients with repeated oral doses of guanfacine (like clonidine, a centrally acting agent with alpha-2 agonist properties) 1-2 mgs/hour. Oral doses of loperamide (4 mgs) and ondansetron (8 mgs) were given, to avoid diarrhea and vomiting during the detoxification procedure.

During the time they were sedated, the subjects' opiate withdrawal signs primarily were piloerection, sneezing and motor agitation.

Four hours after the sleep induction, the patients received a naloxone test (0.8 mgs IV), and then 12 hours later they received 50 mgs of naltrexone, both of which provoked no withdrawal responses.

While Dr. Loimer's initial barbiturate procedure has relieved patients of the conscious symptoms of withdrawal by administering general anesthesia simultaneously with a large continuous dose of a pure narcotic antagonist, he requires patients to be anesthetized for 12 to 24 hours. This is because barbiturate anesthesia tends to accumulate and is not reversible, requiring patients to be monitored for an extended period of time following the procedure. It also minimizes the options available to the physician if adverse conditions arise, such as severe respiratory suppression.

The use of the benzodiazepines, such as midazalom is completely reversible by antagonists such as flumazenil, an imidazobenzodiazepine derivative. Flumazenil competitively inhibits the activities at the benzodiazepine recognition site on the brain's receptor complex. Unfortunately, if the patient is dually-addicted to heroin and benzodiazepines, such as Zanax, Halcion, or Valium, the use of flumazenil to reverse the effects of benzodiazepine anesthesia can cause seizures.

In a 1993 Spanish survey of 973 heroin addicts, 68% of the patients admitted to using benzodiazepines, and 43% admitted to using them on a daily basis. It has been observed that heroin-dependent patients often use benzodiazepines in the days and weeks prior to seeking treatment to help them sleep when they are trying to cut down on their own. These reported figures are believed to be conservative since addicts have no trouble concealing their benzodiazepine use from their treating physician, even when provided with a warning of adverse side effects.

The duration of action for flumazenil may also not be sufficient to eliminate the effects of benzodiazepines which are still present in the patient's blood and bile. This can lead to resedation, and requires extended periods of observation. Of course, extended observation is usually associated with additional nights in a hospital and added expense.

Accordingly, there is a need for rapid opiate detoxification procedure which is safe for both opiate and dually-addicted patients. There is also a need for an effective detox therapy which can permit the swift discharge of ambulatory patients without latent anesthetic side effects.

SUMMARY OF THE INVENTION

Methods of detoxifying patients addicted to opioids are provided by this invention. In the preferred method, the patient is first sedated with a rapid-acting, anesthetic agent having a recovery period of no greater than about 20 minutes, after which said patient is fully awake. The patient is then intubated in order to minimize aspiration, and ventilated to provide oxygen during sedation. The patient is next paralyzed with a neuromuscular blocking agent which cuts down on motor function, permits a reduced dose of anesthetic agent, and decreases the chance of vomiting. The patient is then detoxified by injecting an aggressive opioid antagonist, preferably at least naloxone hydrochloride. Once the patient has been fully detoxified, he or she is quickly and permanently revived from the effects of the anesthetic or neuromuscular blocking agents and then extubated prior to being discharged within a total of about eight hours after initiating therapy.

The detoxification procedures of this invention can be accomplished without requiring an overnight stay at a hospital. The detoxification is preferably accomplished within about three or four hours, while the patient is asleep.

The present invention is a vast improvement over existing ROD procedures which use barbiturates as the lone sedative. The preferred anesthetic agent of this invention, propofol, effectively reduces the symptoms of opiate withdrawal without significant accumulation by the patient's tissues, or the re-introduction of partially metabolized sedative in the patient's blood and bile. Thus, patients detoxified with the procedures of this invention need not be monitored for extended periods of time after they are awake and will have a quick recovery period shortly after terminating the preferred propofol drip.

This invention is also much better than techniques relying solely upon benzodiazepine anesthetics. Propofol controls more of the withdrawal symptoms than benzodiazepines, and the present procedure presents a much lower risk of aspiration than when benzodiazepines are employed. Moreover, eliminating the sedative effects of propofol can be safely accomplished by terminating the intravenous drip, which permits the patient to be fully ambulatory within minutes. Benzodiazepines usually require the introduction of a benzodiazepine receptor antagonist, such as flumazenil, for reversal. Generally, flumazenil doses of approximately 0.421 mg usually produce antagonism in patients who have received the usual sedating doses of benzodiazepines. The onset of reversal is usually evident within one to two minutes after the injection is completed, but resedation, as explained above, is a lingering problem. Despite the quick-initiation of reversibility of benzodiazepines with flumazenil, this chemical reversibility has also been associated with the occurrence of seizures. Such seizures are most frequent in patients who have been on benzodiazepines to help kick their opiate habits. Reversing the sedation effects of propofol are completely without this risk.

In another preferred embodiment of this invention, an opioid detoxification therapy is provided for patients who are dually-addicted to opiates and benzodiazepines, for example, heroin and valium. The patient is first sedated using a rapid-acting intravenous, anesthetic agent, preferably propofol. Following sedation, the patient is administered a narcotic antagonist containing naloxone hydrochloride to induce withdrawal. After withdrawal has been complete, which can be confirmed with a test dosage of naloxone, the patient can be revived by at least terminating the intravenous delivery of the anesthetic agent.

Definitions

naloxone hydrochloride: 1-N-Allyl-7,8-dihydro-14-hydroxymorphinone hydrochloride; a potent antagonist of endorphins and narcotics, including pentazocine; devoid of pharmacologic action when administered without narcotics.

naltrexone: 17-(Cyclopropylmethyl)-4, 5-epoxy-3, 14-dihydroxymorphinan-6-one; an orally active narcotic antagonist; devoid of pharmacologic action when administered in the absence of narcotics.

propofol: an oil-in-water emulsion of 1, 6-diisopropylphenol, a hypnotic with rapid onset and short duration of action; used intravenously for induction and maintenance of general anesthesia. Also called 2, 6-diisopropyl phenol.

opioid: opiates, synthetic narcotics, alcohol, cocaine, cannabis, and other mood-altering substances.

opiate: any preparation or derivative of opium, including heroin.

A DETAILED DESCRIPTION OF THE INVENTION

The present invention provides for rapid detoxification of opioid addicts, including those who are dually-addicted to opiates and benzodiazepines.

An outline of the preferred therapy will now be described as an overview. At the initial office visit, a staff member conducts a biopsychosocial interview. At this time, the procedure is explained in depth along with a description of what to expect after detoxification is complete. The importance of group therapy and a support person following therapy is explained to the patient.

A complete history and physical examination is conducted, with a particular attention directed to prior difficulties with anesthesia on the part of the patient or his or her family. In addition, the arms and legs of the patient should be inspected for adequate venous access. An informed consent form is reviewed and executed, and warnings are given concerning what the patient should expect from the procedure.

The sedation procedure preferably involves the use of a rapid sequence induction of anesthesia, in combination with a rapid-acting, intravenous anesthetic agent. Propofol is a preferred rapid-acting intravenous anesthetic agent. Propofol has a half-time of the blood-brain equilibriation of about one to three minutes. Additionally, propofol is known to reverse its effects within minutes. Discontinuation of recommended doses of propofol injection after the maintenance of anesthesia for approximately 1-10 hours results in a prompt decrease in blood propofol concentrations and rapid awakening in less than 20 minutes, and usually within about 10-15 minutes. This is a drastic improvement over barbiturate anesthesia which is known to take hours for complete reversal.

In addition to the induction and sedation agents, the patient is preferably administered a dose of curare and succinylcholine, an effective, inexpensive paralytic agent commonly used in an induction. Paralysis is desirable since it significantly decreases the incidence of vomiting, however, this requires ventilation since it is necessary to breathe for the patient. After paralysis is induced, it can be maintained with pavulon or norcuron until the therapy is complete.

The patient should also be intubated for protecting the airway. When inducing withdrawal in a patient, particularly a severe withdrawal through the use of a narcotic antagonist, vomiting is a frequent side effect. In order to prevent aspiration of this vomitus, with possible life-threatening consequences, a tube can be placed in the airway with an inflated cuff.

After the patient has been intubated and ventilated, a preferred propofol drip is initiated intravenously. The effects of this intravenous anesthetic agent can be completely eliminated merely by discontinuing its administration. This sedative is also safe to use with dually-addicted patients, such as those that have both heroin and benzodiazepine addiction. In the event that adverse pulmonary or respiratory effects occur during detoxification, the patient can be revived nearly immediately. This is not the case with conventional ROD procedures.

In addition to intubation, a nasogastric tube should be inserted into the stomach cavity of the sedated patient. This allows for the insertion of naltrexone, an oral pure narcotic antagonist during the procedure. It also permits the evacuation of the stomach at any time during the procedure, which tends to lessen the production of vomitus should the person regurgitate.

Following sedation and paralysis, the patient is administered an IV of naloxone initially in a dose of at least about 0.4 mgs. This basically initiates withdrawal, typically exhibited by piloerection and a transient elevation of blood pressure. It acts rapidly and is short-acting. The abstinence syndrome can be seen immediately, and if any complications arise, the procedure can be abandoned in its early phase.

After withdrawal initiates, the naloxone dosage can be increased to about 12 mgs intravenously, or a smaller dose of a stronger or longer-acting antagonist, such as nalmefene or naltrexone can be administered. This large dose will rapidly strip all of the receptors of opiates.

At about three or four hours, the patient should be fully detoxed, and a maintenance dose of opiate antagonist can be administered. This can be made through oral therapy, for example, by naltrexone, or alternatively, as a subcutaneous injection, implantation or insertion under the skin of the patient with a time-released antagonist-carrier mixture. Preferred carriers could include starch, cellulose or polymeric substances. Such materials should be biodegradable within the human body, and can include, for example, rod-shaped, injectable time-released naltrexone dosages combined with a water soluble glass, or a polymer, such as cross-linked polysiloxane copolymers, ethylene-vinyl acetate, and polyurethanes. See U.S. Pat. Nos. 5,141,748; 5,088,505; 4,957,119 and 3,887,699, which are hereby incorporated by reference. Such compositions can also include time-release agents, erosion rate modifiers, antimicrobial agents and surfactants. Alternatively, a mechanical device may be used to create a time-lapsed delivery of the preferred long-acting antagonist substances.

The antagonist maintenance therapy preferably continues to release a minimum therapeutic dose at least once every three days, at least for one week following the procedure. This dose should eliminate the mood-altering effects of any opiate that the patient takes, and will help to maintain sobriety while the patient seeks counseling.

The stomach may be evacuated to avoid any vomiting upon awakening the patient. Additional medications, such as cholesteramine or potassium, can be injected to decrease diarrhea or correct electrolyte imbalances. Paralysis is reversed with a known regiment of a paralytic agent antagonist, and the propofol drip is terminated.

Further specific details of the therapy will now be described in the following example.

EXAMPLE

The patient disrobes and is placed in a hospital bed. A certified registered nurse anesthetist is introduced and reviews the pertinent anesthesia questions with the patient. IV access is established in a peripheral vein with one liter of lactated ringers solution. All subsequent medications will be administered through the intravenous tubing, minimizing needle sticks. A small amount of local anesthetic agent is administered intravenously. The patient is administered 2-3 mg of propofol for the purpose of relaxation. The patient is connected to blood pressure, pulse, pulse oximeter, respiratory, EKG, and end-expiratory CO₂ monitoring. (Defibrillator and all emergency drugs are immediately available).

The physician is present throughout the induction and administration of pure narcotic antagonists which is performed in conjunction with the CRNA. A propofol infusion is prepared and accessed to the patient (50 ml vial of 10 mg per ml). Strict aseptic precautions are observed in preparation. A bolus injection of propofol (20 ml via of 10 mg per ml) is prepared and a dose of 2 mg per kg is injected. Simultaneously, the propofol drip is commenced at 100 micrograms per kg per minute (6 mg per kg per hour). The patient is ventilated, intubated and placed on the ventilator. Cricoid pressure is applied during the intubation. Vital signs are recorded every five minutes during induction of anesthesia and every 30 minutes thereafter for the remainder of the procedure. Pavulon 0.1 mg per kg bolus is injected initiating neuromuscular blockade. This facilitates ventilation and prevents vomiting. The patient is then administered Glycopyrrolate 2 mg IV. This atropine-like medication decreases the marked secretions that patients typically produce during withdrawal. An orogastric tube is then placed and the stomach is evacuated. The patient is administered naloxone 0.4 mg IV and observed for signs of withdrawal, i.e., piloerection and increased blood pressure.

Naloxone is used due to its short half-life. It will initiate the withdrawal sufficiently and still allow an opportunity to abandon the procedure even at this point.

The patient is then administered nalmefene 2 mg IV. This drug occupies approximately 50% more of the receptor sites than naloxone and has a longer half-life (10.8 hours).

The patient is then administered naltrexone 50 to 200 mg via the orogastric tube. This initiates the oral therapy with a long-acting agent. Neuromuscular blockade is maintained with norcuron 0.08 to 0.1 mg per kg based upon the patient's response to peripheral nerve stimulation. After three hours, the stomach is again evacuated. Cholestyramine 8 mg is then administered via the orogastric tube. This is for the prevention of diarrhea. At the end of the procedure, approximately 3.5 hours after the induction, the propofol drip is discontinued. The neuromuscular blockage is reversed with neostigmine 2.5 mg and atropine 1 mg IV bolus. This will also decrease abdominal discomfort after the procedure.

The patient is extubated after the following criteria are met: (a) train of four on peripheral nerve stimulation, (b) swallowing, (c) responds appropriately to verbal stimuli, and (d) sustained head lift of six seconds. The OG tube is removed with the endotracheal tube. A medical alert bracelet or necklace is applied to the patient. After about one hour of observation, within which the patient is assisted in getting dressed, he or she is then assisted out to the car. The physician is present at the termination of the procedure and during extubation.

In the post-procedure phase, the patient is very tired, weak and lethargic, and sleep may appear restless accompanied by extensive yawning. Leg and back pains are usually minimal and are relieved by either hot baths or wet/hot compresses. It is essential that the patient take the naltrexone at least once a day, at least for the first week after the procedure. Instructions are again reviewed with the caretaker. Those instructions include what to expect in the post-procedure phase. The caretaker is instructed to call the doctor upon arriving home. The caretaker is provided with the following: 12 capsules containing phenobarbital 250 mg with clonidine 0.25 mg (these medications are administered for the relief of nausea, vomiting, abdominal cramps and insomnia as directed by the physician); one rectal suppository containing phenobarbital 500 mg with clonidine 0.5 mg; and a prescription for naltrexone 50 mg to be taken one daily, dispense 30. The caretaker is instructed to contact the physician upon arrival at home. Contact is then made by telephone between the caretaker and the physician according to the following schedule: every two to three hours on the first day, and every six hours on the second day. Thereafter, contact is made between the patient and/or caretaker and the physician and/or a staff member daily for one week; then every three to four days for one week, followed bi-weekly for two weeks and periodically thereafter.

We give aggressive telephone support to encourage a connection between the patient and a 12-step recovery program. We try to give guidance in obtaining a sponsor and attempt to communicate with the patient's sponsor in order to help facilitate the transition to a support group. Follow-up office visits are scheduled at weekly intervals for two weeks, then bi-monthly for two months, then monthly and as needed thereafter. Again, this is primarily to facilitate the transition to a 12-step recovery program support structure.

From the foregoing, it can be realized this invention provides improved ROD procedures capable of being safely reversed even in the instance where the patient is dually-addicted to benzodiazepines and heroin. The present invention preferably takes advantage of the fast-acting aesthetic ability of propofol, and uses other techniques, such as paralysis, in rendering the detoxification process almost completely without symptoms. Although various embodiments for these therapies have been illustrated, this was for the purpose of describing, but not limiting the invention. Various modifications, which will become apparent to one skilled in the art, fall within the scope of this invention described in the attached claims. 

What is claimed is:
 1. A method of detoxifying a patient addicted to one or more opioids, comprising:sedating said patient, said sedating step comprising the administration of an a rapid acting, intravenous anesthetic agent having a recovery period, after termination of the administration of said anesthetic agent, of no greater than about twenty minutes; intubating said patient in order to minimize aspiration of vomitus; ventilating said patient for providing oxygen during said sedation; paralyzing said patient with a neuromuscular blocking agent; detoxifying said patient by injecting an opioid antagonist; reviving said patient from the effects of said anesthetic and neuromuscular blocking agents; extubating said patient; and administering antagonist maintenance therapy to said patient by time-releasable subcutaneously implanted antagonist, wherein said steps of sedating, intubating, ventilating, paralyzing, detoxifying, reviving and extubating said patient are completed within about eight hours.
 2. The method of claim 1 wherein said detoxifying step is completed within about four hours, and wherein said implanted antagonist comprises naltrexone.
 3. The method of claim 1 wherein said anesthetic agent comprises 2,6-diisopropylphenol.
 4. The method of claim 1 wherein said opioid antagonist comprises 17-allyl-4, 5 α epoxy-3, 14-dihydroxy-morphinan-6-one hydrochloride.
 5. The method of claim 1 further comprising inserting a nasogastric tube within said patient for administering a longacting opiate antagonist.
 6. The method of claim 2 wherein said reviving step comprises terminating said sedating step and chemically reversing said paralyzing step.
 7. The method of claim 1 further comprising administering a long-acting opiate antagonist to said patient.
 8. The method of claim 1 wherein said sedating step comprises administration of a bolus injection of an anesthetic agent and a subsequent propofol intravenous drip. 